Procedure at 1600 RPM

The ignition timing can be adjusted according to the following primary timing procedure.
Preparation:
- Set the parking brake.
- Shift automatic transmissions to PARK and manual transmissions to the neutral position.
- Start the engine and allow it to attain normal operating temperature.
- Ensure that the A/C is turned OFF, if equipped.
Procedure:
- With the ignition switch OFF, connect an ignition timing light and a calibrated, expanded scale tachometer.

NOTE: If the timing light has an adjustable advance control feature, turn the control to the OFF position.

- Disconnect the 3 wire connector from the four-and-ten-inch Hg (Computerized Engine Control System) vacuum switch assembly wire connector (located at the top of the cylinder head cover).
- Disconnect and plug the distributor vacuum advance hose.

WARNING: Use extreme caution when the engine is operating. Do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or the fan. Do not wear loose clothing.

- Start the engine.
- Increase the engine speed to 1600 rpm and check the ignition timing.
- If necessary, adjust the timing to the specification listed on the Emission Control Information label.










- Also, refer to the ignition advance curve illustrations.
- Tighten the distributor hold-down clamp and verify that the ignition timing is correct.
- Turn the engine OFF and remove the timing light and tachometer.
- Connect the number one spark plug wire, if disconnected.
- Connect the hose to the distributor vacuum advance mechanism.
- Connect the wire connector to the vacuum switch assembly.